1. Field of the Invention
The present invention relates to devices that can be used as actuators or as motors which are easy to form, which use low-cost fuel, and which emit little or no waste.
Further, the present invention relates to devices which can be used as actuators or as motors capable of operating within a biological medium such as the human body or an animal body.
Such actuators and such motors find applications in the medical field, for example, to overcome the impairment of a natural muscle. Muscles that can be replaced or assisted, temporarily or definitively are, for example, the heart muscle, the respiratory muscles, the sphincters, and smooth or striated muscles, in particular skeletal muscles.
Such actuators and such motors also find applications in fields other than the medical field. In particular, such a motor may be used in all fields where a low waste generation is an important factor in selecting the motor. It may be, for example, the automobile field where the polluting waste generated by the motor used to drive the vehicle wheels is desired to be decreased as much as possible.
2. Discussion of the Related Art
US patent application 2004/248269 of the applicant describes an osmotic actuator intended to be dipped in a biological medium and comprising a deformable enclosure having a semi-permeable membrane, the enclosure containing a solute likely to be osmotically active.
Patent application EP-A-1481165 of the applicant describes an actuator and an osmotic motor with an operation that can be controlled with more accuracy. For this purpose, patent application EP-A-1481165 provides use of microorganisms which are contained in an enclosure permeable to a solvent and impermeable to a first solute. The microorganisms are capable of transforming a second solute into the first solute. A deformable chamber is connected to the enclosure and can see its volume increase under the action of the solvent penetrating into the enclosure by osmosis as the microorganisms are providing the first solute.
A disadvantage of such an actuator and of such an osmotic motor is that keeping microorganisms alive imposes constraining conditions of use. More specifically, it is necessary to dissolve, in the solvent in which the microorganisms are arranged, substances essential to the metabolism of the microorganisms, for example, glucose and oxygen. It is further necessary to provide the discharge of the waste generated by the cellular metabolism, especially the carbon dioxide. Further, it is necessary to maintain many parameters such as temperature or the pH of the solvent in which the microorganisms are arranged within generally very small ranges out of which microorganisms cannot survive.